Friction member



Feb. '24, 1925. I 1,527,293

w. T. BONNER FRICTION MEMBER Filed March 18, 1920 f I V 12 3. {2 0.4

prior/4ft.

Patented Feb. 24,1925.-

UNITED STATES I 1,527,293 PATENT orrics.

WILLIAM BONNER, 0F TRENTON, NEW JERSEY, ASSIGNOR T0 MAX BROWN, 01

. BOSTON, MASSACHUSETTS.

rmorron MEMBER.

Application filed March 18,.1920. Serial No. 366,944.

To all whom it may concern:

Be it known that I, WVILLIAM T. BONNER, a-citizen of the United States, residing at Trenton, in the county of Mercer and State of New Jersey, have invented a new and useful Improvement in Friction Members, of which the following is a specification.

I have discovered that the alkaline metal magnesium, and alloys thereof hereinafter described, possess friction value of a high order and sufficient strength to transmit power. Ifhavej also discovered that the coefficient of friction of magnesium and its alloys may be increased by alloying'therewith either of the metals sodium, potassium, or calcium, and that the tensile strength of a friction member made of such metalor alloys may be increased by alloying manganese therewith. By alloying from two to three parts ofthe metal manganese with ninety-eight or ninety-seven parts -of the metal magnesium I produce an alloy pos-" 'sessing greater tensile strength than is possessed by the pure metal magnesium without an appreciable loss ofits friction value. The friction value of such described alloy can be increased, if-desired, by the addition of the metal sodium in theproportion of one-half of one part of sodium to ninetynine and one half parts of the said alloy.

The proportions of the different metals in the alloys nientioned may be varied somea form in common use in automotive ve what without seriouslychanging the mentioned qualities of the alloys, but I" prefer to-adhere rather closely to the proportions which I have named, Either the metal potassium or the metal calcium may be substituted for the metal sodium in such alloys in similar proportions with similar results. The metal sodium, like potassium on calcium, being of an unstable nature and a rapid absorbent of oxygen, imparts that. quality, in a lesser degree, to such alloy of Which it is a constituent element and raises the friction value of the alloy.

While I describe and prefer for the uses mentioned, the metal magnesium and its.

alloys, I have also discovered that other metals, such as aluminum, zinc, and cop per, when alloyed with what are known as unstable 'metals,. such as sodium, potassium, and calcium, obtain a capacity for the absorption of oxygen in a greater degree than is possessed by such metals when unal-' loyed, resulting ina large gain of friction value; and this without the loss of that ten-' sile strength which is essential to their use in friction members. The metal magnesium, unalloyed, I have also found to possess a desirable coefficient of friction and sufficient tensile strength to be useful as a material for friction elements without being used in excessive mass in construction.

The lightness, or lOW specific gravity, of

magnesium, and its described alloys, their high friction value, and their remarkable endurance of frictlonal wear, make them very'deslrable as materials for use in the construction of friction members, such as.

clutches and brakes; and especially so when such friction elements are used in automotive vehicles in which the combined qualities of lightness, strength and durability of parts are highly essential.

Viewed, then, in its broad aspect, my invention consists in the utilization of my discovery of the friction values of the aforesaid metal magnesium and of various alsaid materials, 4 whereby great advantages are gained in reduction of mass, diminution in weight, greater eificiency, and largely increased longevity of such members 1n servn-this specification' I illustrate my in vention as embodied in clutch mechanism of hicles.

In the clutch or friction drive, as employed chiefly on automotive conveyances, to transmit the power of the engine to the driving mechanism, one or more metal discs are employed. Where only one disc is used the clutch or drive-is usually known as a single disc clutch, while, if a plurality of discs are used, the construction is known binder. In the construction of single disc loys, by constructing friction members of clutches the disc is frequently made wholly of such fibrous or fabric material so united and hardened. The friction discs described, when composed of a metal disc with a facing of fibrous or fabric material on one or on each of its faces, is a composite structure expensive to manufacture and has to be freuently replaced because of the wear and. estruetion of its frictional facings, while the discs made wholly of fibrous or fabric material are subject to the same objections. By constructing these friction discs of a metal or alloy possessing both the requisite tensile strength and a high friction value I reduce the bulk of those elements, the size of their housings, and the weight of the entire structure of the clutch, and obtain a greatly increased length of service, approximately equal to that of the other parts of the mechanism with which they are combined, while the cost of the original construction is materially lessened.

Referring to the drawings forming a part of this specification, wherein an illustrativeembodiment of the invention is shown,

I Fig. 1 shows in side elevation a clutch element embodying the invention;

Fig. 2 is a transverse'diametrical section thereof;

Fig. 3 is an elevation showing a preferred form of clutch disc with attached friction facing in common use; and,

Fig. 4 is a transverse diametrical section thereof.

10 indicates a clutch disc which may be employed for either 'a'multiple disc clutch or a single disc clutch. This disc is composed ofmetallic magnesium, or a suitable alloy thereof, or, in a broader aspect, it may be composed of other materials, already named as having a relatively high co-efiicient of friction, while also having sufficient inherent strength and toughness to withstand the service usage in a clutch without other reinforcement or backing. This disc or ring may be equipped with notches or projections for engaging a key-way in its periphery, as

- indicated at 10*. It will be understood that these notches or key-way engagements are produced upon the outer periphery of the ring, since these rings or discs correspond to, and are to take the place ofthe composite discs equipped with friction rings or facings hitherto employed. The intermediate metal'discs, usually of iron or steel, operate directly against the faces thereof, having their engaging notches or key-ways upon the inner circle or periphery of the ring. This improved friction element thus takes the place of the composite ring illustrated in Figs. 3 and 4, wherein a metallic packing ring 11 of iron or steel and equipped with outer peripheral notches, 11 is provided, and on one or both sides thereof friction facings, 12, are secured by riveting, or otherwise. These faces are usually of a composition comprising compressed fibrous or textile material united with a suitable cementitious binder.

As other modifications and specific forms of the invention may be employed, I desire the present embodiment to be considered in all respects as illustrative, and not restrictive, and refer to the appended claims rather than to the foregoing descri tion, to indicate the scope of the invent1on,,which, in

effect, is the construction of friction members, in the broad sense of that term, of whatever form, or to whatsoever use they may be applied, of the metal, or alloys, possessing the friction value referred to herein.

,Having described my invention, what I claim as newand desire to secure by Letters Patent, is;

1. A friction member comprising upwards of ninety percent of metallic magnesium, and less than ten' percent of an alkaline metal as described, possessing suflicient strength to receive transmitted power and a relatively high co-eliicient of friction to deliver the power so received to one or more contacting elements.

2. A friction member of metallic magnesium possessing, as described, sufficient inherent strength to receive upon its surface or periphery, transmitted ower, and possessing a relatively high friction value, suflieient to transmit frictionally from its operative sides or faces, the power so received to one or more contacting surfaces.

3. A friction member comprising upwards of ninety percent of metallic magnesium alloyed with a minor proportion of strength giving metal as described, possessing sufiicient inherent strength to receive transmitted power, and possessing'upon its operative sides or faces a relatively high value in friction efficiency adapted to transmit the power received to one or more contacting surfaces.

4. A friction member for clutches of automotive vehicles, of metallic magnesium in one piece, possessing, as described, suilicient strength to receive upon its surface or periphery power transmitted, and possessing a relatively high friction value sufiicient to transmit from its operative sides or faces frictionally, the power so received to one or more contacting surfaces.

In testimony whereof, I have \signed my name to this specification.

WILLIAM T. BONNER. 

